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The incidence of sudden sensorineural hearing loss did not differ significantly between the HIV group and the control group for patients 36 and older

Having HIV appears to increase the risk of sudden sensorineural hearing loss, at least among younger patients, researchers reported.

Compared with HIV-negative controls, people living with HIV who were 35 or younger had double the risk of sudden hearing loss, according to Yung-Song Lin, MD, of Taipei Medical University in Taiwan, and colleagues.

But, in a retrospective population-based cohort, there was no significant difference between the groups for people 36 or older, Lin and colleagues reported online in JAMA Otolaryngology-Head & Neck Surgery.

Up to 44% of HIV-positive people have a chronic hearing impairment, for a variety of reasons, Lin and colleagues noted. Sudden sensorineural hearing loss in HIV-positive people, on the other hand, has been reported occasionally but there are no case series or cohort studies of the condition in those with the virus.

To help fill the gap, they looked at medical records from the country's national health insurance system on a cohort of 8,760 HIV-positive people diagnosed between Jan. 1, 2001, and Dec. 31, 2006.

For comparison, they included 43,800 people with other insurance claims but without HIV.

In Taiwan, Lin and colleagues noted, sudden sensorineural hearing loss is defined as loss of 30 decibels or more in at least three contiguous audiometric frequencies that develops over a period of a few hours to 3 days.

To account for the effect of age, the study cohort was divided into those 18 through 35, and those older than 35.

In the younger HIV-positive group, Lin and colleagues found, there were 11 cases of the condition in 25,439 person-years of follow-up. Among the younger controls, there were 26 cases in 130,722 person-years of follow-up.

Those numbers yielded incidence rates of 4.32 and 1.99 cases per 10,000 person-years, respectively, for an incidence rate ratio of 2.17, which was significant at P=0.03.

The incidence rate ratio for sudden hearing loss was significantly elevated only in men; it did not reach significance among the 11% who were women.

In a Cox proportional hazards regression model with propensity score matching, the hazard ratio in the younger group -- adjusted for age, sex, geographic region, and annual income – was 2.17 (95% CI 1.07 to 4.4).

In contrast, among the older participants, there were five cases in 15,506 person-years of follow-up among those who were HIV-positive and 39 cases in 87,570 person-years of follow-up among the controls.

That yielded incidence rates of 3.22 and 4.45 cases per 10,000 person-years, respectively, and a nonsignificant incidence rate ratio of 0.72.

Lin and colleagues said it remains unclear why the effect was only seen among those 35 or younger. Indeed, they cautioned that a population-based study "cannot explore the underlying mechanism" that might link HIV and sudden sensorineural hearing loss.

They noted, too, that some possible risk factors – such as smoking history and noise exposure – were not included in the insurance database, and their absence might have introduced some bias.

Finally, the data did not include information about the severity of hearing loss or other laboratory test results, they noted.

The study was supported by the Chi Mei Medical Center research fund of Taipei Medical University.

The journal said the authors made no conflict of interest disclosures.

Reviewed by Zalman S. Agus, MD Emeritus Professor, Perelman School of Medicine at the University of Pennsylvania and Dorothy Caputo, MA, BSN, RN, Nurse Planner

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